Present day electronic devices must often generate one or more waveform signals as part of their functionality. For example, a waveform generator may be configured to generate any number of different waveforms that may be output by the device. As another example, automated integrated circuit testers such as the Agilent 93000 SOC Series Automated Tester Environment (ATE), manufactured by Agilent Technologies, Inc. of Palo Alto, Calif., may require generation of waveform signals on various pins of the tester for application to pins or pads of an integrated circuit device under test (DUT).
Electronic devices that produce waveform signals often store representations of the waveform signals (hereinafter referred to as “waveforms”) in dedicated waveform registers or memory (collectively referred to hereinafter as “waveform table”). Memory is always a limiting factor in the number of waveforms that may be stored in the waveform table. Therefore, the number of registers or locations in memory (collectively referred to hereinafter as “waveform table entries”) available for storing waveforms is limited. Cost and speed are limiting factors in the size of the waveform table. Typically, fast memory is required for waveform generating circuitry, and fast memory is more expensive. Accordingly, a common solution is to simply limit the number of waveforms that can be generated by the hardware.
Situations exist, however, where it may be desirable to be able to expand the number of waveforms available by a test program beyond a limited number of waveforms that may be generated by the hardware. In an integrated circuit tester, for example, test software generates test programs that may be executed by tester resources to generate waveforms on various pins of the tester for application to pins and pads of an integrated circuit under test to test various aspects of the integrated circuit. However, since the waveform table can store only a limited number of waveforms, and the waveforms must be available for generation of the waveforms on the tester pins, the test software typically limits the number of waveforms that any given test program generated by the test software may define to the number of available waveform table entries. However, it would be desirable in many applications, for example in memory test applications, to be able to generate a number of waveforms that exceed the number of waveforms limited by the size of the waveform table. Currently, no technique exists for such expansion without altering the hardware.